Mobile devices such as gas-measuring devices, especially portable gas-measuring devices, are used, in industrial plants, business premises and public buildings, wherever humans and property have to be protected against injuries and damage. The gas concentration of at least one gaseous substance can thus be monitored in a large industrial plant such as a refinery. The gas concentrations to be monitored concern, for example, the lower explosion limit or threshold values of gases, for example, carbon monoxide, hydrogen sulfide, oxygen, or other toxic gas substances. Lower explosion limit is defined as the limit that leads to explosion when coming into contact with an external energy source, for example, a spark. A toxic gaseous substance is generally designated as a gaseous or vaporous hazardous material which has specific hazardous properties or other chronically damaging properties. Gas-measuring devices known in the state of the art generally possess one or more gas inlet openings, through which the gaseous substance to be tested is fed to corresponding sensors in order to measure the gas concentration of the corresponding gaseous substances. An optical and/or acoustic alarm is triggered if it is detected in a gas-measuring device that the concentration of a toxic substance of the gas being tested exceeds a defined threshold value. To guarantee a reliable operation of such gas-measuring devices, a maintenance, i.e., to test, to adjust and/or to calibrate them, is required at regular intervals. A test is essentially defined as a simple test of operation of a gas-measuring device. Regular settings are made during an adjustment in order to check and to set the zero point and the sensitivity of the gas-measuring device with a known zero gas or test gas without parameters, e.g., gas species, measuring range, alarm thresholds and special applications set during the initial startup being changed. During a calibration, the display of the gas-measuring device is compared with a known test gas concentration.
For testing, adjusting and/or calibrating gas-measuring devices, a test station is known, for example, from DE 10 2012 210 085 B3 for a portable gas-measuring device for at least one test gas with a device for receiving the gas-measuring device, a test gas supply, a pivotable flap for covering at least one area with gas inlet openings of the exposed surface of a gas-measuring device received in the receiving area and with a seal. A method for operating a gas concentration monitoring system for detecting the gas concentration of at least one gaseous substance is known from DE 10 2011 119 570 A1.
Further, interconnecting a plurality of such test stations in a storage device in order to make possible the maintenance of a plurality of gas-measuring devices at the same time is known in the state of the art. However, a disadvantage of such storage devices is that the individual maintenance stations are very expensive and thus lead to considerable costs for such storage devices. In addition, in storage devices available in the state of the art, which consist, for example, of a plurality of docking stations for gas-measuring devices, there is the risk that non-maintained gas-measuring devices will also be released to the user, because they can be simply removed from the docking station. It is also known to display the maintenance status of a gas-measuring device via a lamp; however, this does not hinder the untrained user from removing a gas-measuring device which is displayed as not maintained by a lamp flashing red, for example. In particular, the user could inadvertently interpret the lamp flashing red, for example, as an indication of a charging state and not for a maintenance status such as a calibration status of the gas-measuring devices.